Ultrasound-guided retrobulbar nerve block in donkey cadavers

Abstract

Objective: To develop and describe an acoustic window to access and inject the retrobulbar region in donkey cadavers. Study design: Prospective cadaveric experimental study. Animals: A total of 14 donkey cadaver heads. Methods: Ultrasound landmarks for retrobulbar injection were identified by dissection of two cadavers. Ultrasound-guided retrobulbar injection of 3, 6 and 9 mL of contrast–lidocaine mixture (1:1) were evaluated using computed tomography (CT) in 12 cadavers for needle position and spread of injectate into the extraocular muscle cone. Results: Real-time visualization of needle, extraocular muscle cone and optic nerve enabled successful intraconal instillation of injectate, as documented on CT images. Conclusions and clinical relevance: Ultrasound-guided retrobulbar injections in cadaver donkeys provided adequate infiltration of the intraconal space.